Systems and methods to detect and prevent bots from random access by randomized http urls in real time in distributed systems

ABSTRACT

Described embodiments provide systems and methods for preventing unauthorized access of information from a resource. A device intermediary between a client and a server in a session can receive a first request from the client that includes a first uniform resource locator (URL) of the server. The device may receive a response from the server that includes a second URL. The device may update the response by including a client identifier for the session in a set-cookie field, obfuscating the second URL into a string, and replacing the second URL in the response with the string. The device may receive a second request that includes a candidate client identifier, and a third URL. The device may determine whether the second request is valid, by at least one of: matching the candidate client identifier with the client identifier, and determining whether the second URL is recoverable using the third URL.

FIELD OF THE DISCLOSURE

The present application generally relates to protecting resources fromunauthorized access, including but not limited to systems and methodsfor preventing malicious entities or bots from randomly accessinginformation from one or more resources and/or services.

BACKGROUND

Certain protocols can execute one or more processes that are vulnerableto unauthorized or malicious attempts to access one or more resources.Some approaches may provide protective mechanisms against said attempts.For example, one or more approaches may configure one or more points ofentry/access to a resource. An authorized user may use the one or morepoints of entry to access a resource and/or navigate/traverse to otherresources. At least one problem with said approaches may be a failure toprovide adequate protection against unauthorized attempts by an attackerto randomly access/traverse the one or more resources. Failing toprovide adequate protection can provide the attacker with opportunitiesto access sensitive/secured information.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features, nor is it intended to limit the scope of the claimsincluded herewith.

The present disclosure is directed towards systems and methods forpreventing malicious entities from gaining unauthorized access toinformation from a resource (e.g., via a uniform resource locator (URL))and/or a service (e.g., an application resource, such as a webapplication, SaaS application or remote-hosted network application). Ifa request to access a resource (e.g., via URLs in requests) is validatedaccording to the systems and methods described herein, a device (e.g., agateway module, a local/foreign node, and/or an application deliverycontroller (ADC)) may recover a URL and/or allow the server to receivethe request with the recovered URL. Otherwise, the device may determinethat the request is invalid, and can prevent and/or preclude the serverfrom receiving the request. In one example, malicious entities, actorsand/or bots may attempt to obtain information of a resource (e.g.,directory structure, folders or content/data/path of a webpage) from aserver (e.g., a backend server supporting hypertext transfer protocol(HTTP) and/or hypertext transfer protocol secure (HTTPS)) for maliciouspurposes (e.g., performing price scrapping and/or automatic formsubmissions). The systems and methods presented herein can prevent theentities and/or bots from obtaining said information byobfuscating/randomizing each URL in a response from the server (e.g.,HTTP RESPONSE). By obfuscating the URL(s), a device can remove path ordirectory structure information of the URL(s) from the response, therebypreventing bots and/or malicious actors from using such information andthe response to improperly access other information of a resource (e.g.,pricing information of a website).

In one aspect, the present disclosure is directed to a method forpreventing unauthorized access, retrieval, storage, and/or usage ofinformation from a resource. The method can include receiving, by adevice intermediary between a client (e.g., a smartphone, a laptop, atablet device, a desktop computer of a user, and/or a client supportingHTTP/HTTPS) and a server in a session, a first request and/or message(e.g., HTTP GET, GET /index.html, and/or other requests) from the clientthat includes a first uniform resource locator (URL) of the server. Thefirst URL can be used to access a first resource of the server (e.g., aresource, service, and/or application hosted on the server). A URL, suchas a first/second URL, can be a URI, a web path, an address, and/orother resource identifiers/locators. In some embodiments, the device maycorrespond to a cluster of devices comprising one or more devices (e.g.,distributed systems). The device may receive a response from the serverthat includes a second URL. The device may update the response byincluding a client identifier (e.g., CLIENT_SESSION_ID, CLIENT_PCK,and/or other identifiers) for the session in a set-cookie field (e.g., aset-cookie HTTP header), obfuscating the second URL into a string, andreplacing the second URL in the response with the string. The device mayreceive a second request that includes a candidate client identifier,and a third URL. The device may determine whether the second request isvalid, by at least one of: matching the candidate client identifier withthe client identifier, and determining whether the second URL isrecoverable using the third URL.

In some embodiments, the device may determine a match between thecandidate client identifier and the client identifier. Responsive to thematch, the device may determine whether the second URL is recoverableusing the third URL. When the second URL is recoverable, the device mayupdate the second request by replacing the third URL in the secondrequest with the second URL recovered using the third URL. The devicemay send the updated second request to the server. In some embodiments,obfuscating the second URL into a string may comprise generating, by thedevice, a URL identifier unique to the second URL. The device cangenerate the string by applying a hash function on a combination of theURL identifier, the client identifier and a domain name of the server.In certain embodiments, the device can maintain a mapping between thestring and the second URL in mapping data for the session. Determiningwhether the second URL is recoverable using the third URL may comprisedetermining, by the device, whether the third URL is in the mapping dataas the string. The device may recover the second URL from the mappingdata according to the string and the mapping.

In some embodiments, obfuscating the second URL into a string maycomprise generating, by the device, a first encryption key using theclient identifier and a key of the device. The device may generate thestring by performing encryption using the second URL and the firstencryption key. In certain embodiments, determining whether the secondURL is recoverable using the third URL may comprise generating, by thedevice, a second encryption key using the candidate client identifier,and the key of the device. The device may perform decryption of thethird URL using the second encryption key. In some embodiments, afailure of the decryption may be indicative that the second URL isunrecoverable using the third URL. In certain embodiments, obfuscatingthe second URL into a string may comprise obfuscating or removing pathor directory structure information in the second URL, from beingaccessible at the client.

In one aspect, the present disclosure is directed to a deviceintermediary between a client and a server for preventing unauthorizedaccess, retrieval, storage, and/or usage of information from a resource.The device may comprise at least one processor. The at least oneprocessor may be configured to receive, in a session, a first requestfrom the client that includes a first uniform resource locator (URL) ofthe server. The at least one processor may be configured to receive aresponse from the server that includes a second URL. The at least oneprocessor may be configured to update the response by including a clientidentifier for the session in a set-cookie field, obfuscating the secondURL into a string, and replacing the second URL in the response with thestring. The at least one processor may be configured to receive a secondrequest that includes a candidate client identifier, and a third URL.The at least one processor may be configured to determine whether thesecond request is valid, by at least one of: matching the candidateclient identifier with the client identifier, and determining whetherthe second URL is recoverable using the third URL.

In some embodiments, the at least one processor may be configured todetermine a match between the candidate client identifier and the clientidentifier. The at least one processor may be configured to determine,responsive to the match, whether the second URL is recoverable using thethird URL. When the second URL is recoverable, the at least oneprocessor may be configured to update the second request by replacingthe third URL in the second request with the second URL recovered usingthe third URL. The at least one processor may be configured to send theupdated second request to the server. In some embodiments, the at leastone processor may be configured to obfuscate the second URL into astring, by generating a URL identifier unique to the second URL. The atleast one processor may be configured to generate the string by applyinga hash function on a combination of the URL identifier, the clientidentifier and a domain name of the server. The at least one processormay be configured to maintain a mapping between the string and thesecond URL in mapping data for the session. The at least one processormay be configured to determine whether the second URL is recoverableusing the third URL by determining whether the third URL is in themapping data as the string. The at least one processor may be configuredto determine whether the second URL is recoverable using the third URLby recovering the second URL from the mapping data according to thestring and the mapping.

In some embodiments, the at least one processor may be configured toobfuscate the second URL into the string by generating a firstencryption key using the client identifier and a key of the device. Theat least one processor may be configured to obfuscate the second URLinto the string by generating the string by performing encryption usingthe second URL and the first encryption key. The at least one processormay be configured to determine whether the second URL is recoverableusing the third URL by generating a second encryption key using thecandidate client identifier, and the key of the device. The at least oneprocessor may be configured to determine whether the second URL isrecoverable using the third URL by performing decryption of the thirdURL using the second encryption key.

In one aspect, the present disclosure is directed to a non-transitorycomputer readable medium storing program instructions for preventingunauthorized access, retrieval, storage, and/or usage of informationfrom a resource. The program instructions stored in a non-transitorycomputer readable medium may cause at least one processor to receive, ina session, a first request from the client that includes a first uniformresource locator (URL) of the server. The at least one processor mayreside in a device intermediary between a client and a server. Theprogram instructions can cause the at least one processor to receive aresponse from the server that includes a second URL. The programinstructions can cause the at least one processor to update the responseby including a client identifier for the session in a set-cookie field,obfuscating the second URL into a string, and replacing the second URLin the response with the string. The program instructions can cause theat least one processor to receive a second request that includes acandidate client identifier, and a third URL. The program instructionscan cause the at least one processor to determine whether the secondrequest is valid, by at least one of: matching the candidate clientidentifier with the client identifier, and determining whether thesecond URL is recoverable using the third URL.

In some embodiments, the program instructions can cause the at least oneprocessor to determine a match between the candidate client identifierand the client identifier. Responsive to the match, the programinstructions can cause the at least one processor to determine whetherthe second URL is recoverable using the third URL.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Objects, aspects, features, and advantages of embodiments disclosedherein will become more fully apparent from the following detaileddescription, the appended claims, and the accompanying drawing figuresin which like reference numerals identify similar or identical elements.Reference numerals that are introduced in the specification inassociation with a drawing figure may be repeated in one or moresubsequent figures without additional description in the specificationin order to provide context for other features, and not every elementmay be labeled in every figure. The drawing figures are not necessarilyto scale, emphasis instead being placed upon illustrating embodiments,principles and concepts. The drawings are not intended to limit thescope of the claims included herewith.

FIG. 1A is a block diagram of a network computing system, in accordancewith an illustrative embodiment;

FIG. 1B is a block diagram of a network computing system for deliveringa computing environment from a server to a client via an appliance, inaccordance with an illustrative embodiment;

FIG. 1C is a block diagram of a computing device, in accordance with anillustrative embodiment;

FIG. 2 is a block diagram of an appliance for processing communicationsbetween a client and a server, in accordance with an illustrativeembodiment;

FIG. 3 is a block diagram of a system for preventing unauthorized accessto (e.g., retrieval, storage, and/or usage of) information from aresource, in accordance with an illustrative embodiment;

FIG. 4 is a communication diagram of a system for preventingunauthorized access to information from a resource, in accordance withan illustrative embodiment;

FIG. 5 is a communication diagram of a system for preventingunauthorized access to of information from a resource, in accordancewith an illustrative embodiment; and

FIG. 6 is a flow diagram of an example method for preventingunauthorized access to information from a resource, in accordance withan illustrative embodiment.

DETAILED DESCRIPTION

Certain protocols (e.g., hypertext transfer protocol (HTTP), hypertexttransfer protocol secure (HTTPS), secure sockets layer (SSL), transportlayer security (TLS), and/or other protocols) may execute one or moremethods (e.g., HTTP GET and/or other methods) that are vulnerable tounauthorized/malicious attempts to access information from one or moreresources (e.g., via one or more uniform resource locators (URLs) of aweb server/service). For example, certain approaches (e.g., startuniform resource locator (URL) check, and/or other approaches) mayprovide, use, and/or configure at least one point of entry/access (e.g.,allowed URLs and/or start URLs) to a server, a service, and/or aresource. An authorized user may use the point(s) of entry to access theresource, server, and/or service, to navigate/traverse to otherresources (e.g., closure URLs), and/or to obtain information fromresources. However, said approaches may fail to provide adequateprotection against unauthorized attempts (e.g., attempts by bots and/ormalicious actors) to randomly access, retrieve, and/or use informationof the other resources, using for example path or directory structureinformation that can be extracted from the point(s) of entry.

For instance, a bot and/or malicious actor can crawl, visit, and/oraccess a webpage (or other resources) and/or a server to obtain and/orstore the content/information/data of the webpage. The bot/actor mayobtain/store information of the webpage for malicious purposes, such asperforming web scraping (e.g., price scrapping) without permission of anowner of the webpage. For example, a bot may perform price scrapping tomaliciously monitor, track, and/or access pricing information of arival/competitor, with the goal of undercutting said rival/competitor toboost/increase sales of a product. In certain scenarios, the bot/actormay store/maintain the obtained pricing information from the webpage toperform automatic form submissions and/or create a fake useraccount/profile (e.g., spamming content on one or more servers). Thesystems and methods described herein can detect and/or preventbots/actors from performing unauthorized web scrapping and/or automaticform submissions in distributed systems in real time.

For purposes of reading the description of the various embodimentsbelow, the following descriptions of the sections of the specificationand their respective contents may be helpful:

Section A describes a network environment and computing environmentwhich may be useful for practicing embodiments described herein;

Section B describes embodiments of systems and methods for delivering acomputing environment to a remote user;

Section C describes embodiments of systems and methods for preventingunauthorized access to information from a resource.

A. Network and Computing Environment

Referring to FIG. 1A, an illustrative network environment 100 isdepicted. Network environment 100 may include one or more clients102(1)-102(n) (also generally referred to as local machine(s) 102 orclient(s) 102) in communication with one or more servers 106(1)-106(n)(also generally referred to as remote machine(s) 106 or server(s) 106)via one or more networks 104(1)-104 n (generally referred to asnetwork(s) 104). In some embodiments, a client 102 may communicate witha server 106 via one or more appliances 200(1)-200 n (generally referredto as appliance(s) 200 or gateway(s) 200).

Although the embodiment shown in FIG. 1A shows one or more networks 104between clients 102 and servers 106, in other embodiments, clients 102and servers 106 may be on the same network 104. The various networks 104may be the same type of network or different types of networks. Forexample, in some embodiments, network 104(1) may be a private networksuch as a local area network (LAN) or a company Intranet, while network104(2) and/or network 104(n) may be a public network, such as a widearea network (WAN) or the Internet. In other embodiments, both network104(1) and network 104(n) may be private networks. Networks 104 mayemploy one or more types of physical networks and/or network topologies,such as wired and/or wireless networks, and may employ one or morecommunication transport protocols, such as transmission control protocol(TCP), internet protocol (IP), user datagram protocol (UDP) or othersimilar protocols.

As shown in FIG. 1A, one or more appliances 200 may be located atvarious points or in various communication paths of network environment100. For example, appliance 200 may be deployed between two networks104(1) and 104(2), and appliances 200 may communicate with one anotherto work in conjunction to, for example, accelerate network trafficbetween clients 102 and servers 106. In other embodiments, the appliance200 may be located on a network 104. For example, appliance 200 may beimplemented as part of one of clients 102 and/or servers 106. In anembodiment, appliance 200 may be implemented as a network device such asCitrix networking (formerly NetScaler®) products sold by Citrix Systems,Inc. of Fort Lauderdale, Fla.

As shown in FIG. 1A, one or more servers 106 may operate as a serverfarm 38. Servers 106 of server farm 38 may be logically grouped, and mayeither be geographically co-located (e.g., on premises) orgeographically dispersed (e.g., cloud based) from clients 102 and/orother servers 106. In an embodiment, server farm 38 executes one or moreapplications on behalf of one or more of clients 102 (e.g., as anapplication server), although other uses are possible, such as a fileserver, gateway server, proxy server, or other similar server uses.Clients 102 may seek access to hosted applications on servers 106.

As shown in FIG. 1A, in some embodiments, appliances 200 may include, bereplaced by, or be in communication with, one or more additionalappliances, such as WAN optimization appliances 205(1)-205(n), referredto generally as WAN optimization appliance(s) 205. For example, WANoptimization appliance 205 may accelerate, cache, compress or otherwiseoptimize or improve performance, operation, flow control, or quality ofservice of network traffic, such as traffic to and/or from a WANconnection, such as optimizing Wide Area File Services (WAFS),accelerating Server Message Block (SMB) or Common Internet File System(CIFS). In some embodiments, appliance 205 may be a performanceenhancing proxy or a WAN optimization controller. In one embodiment,appliance 205 may be implemented as Citrix SD-WAN products sold byCitrix Systems, Inc. of Fort Lauderdale, Fla.

Referring to FIG. 1B, an example network environment, 100′, fordelivering and/or operating a computing network environment on a client102 is shown. As shown in FIG. 1B, a server 106 may include anapplication delivery system 190 for delivering a computing environment,application, and/or data files to one or more clients 102. Client 102may include client agent 120 and computing environment 15. Computingenvironment 15 may execute or operate an application, 16, that accesses,processes or uses a data file 17. Computing environment 15, application16 and/or data file 17 may be delivered via appliance 200 and/or theserver 106.

Appliance 200 may accelerate delivery of all or a portion of computingenvironment 15 to a client 102, for example by the application deliverysystem 190. For example, appliance 200 may accelerate delivery of astreaming application and data file processable by the application froma data center to a remote user location by accelerating transport layertraffic between a client 102 and a server 106. Such acceleration may beprovided by one or more techniques, such as: 1) transport layerconnection pooling, 2) transport layer connection multiplexing, 3)transport control protocol buffering, 4) compression, 5) caching, orother techniques. Appliance 200 may also provide load balancing ofservers 106 to process requests from clients 102, act as a proxy oraccess server to provide access to the one or more servers 106, providesecurity and/or act as a firewall between a client 102 and a server 106,provide Domain Name Service (DNS) resolution, provide one or morevirtual servers or virtual internet protocol servers, and/or provide asecure virtual private network (VPN) connection from a client 102 to aserver 106, such as a secure socket layer (SSL) VPN connection and/orprovide encryption and decryption operations.

Application delivery management system 190 may deliver computingenvironment 15 to a user (e.g., client 102), remote or otherwise, basedon authentication and authorization policies applied by policy engine195. A remote user may obtain a computing environment and access toserver stored applications and data files from any network-connecteddevice (e.g., client 102). For example, appliance 200 may request anapplication and data file from server 106. In response to the request,application delivery system 190 and/or server 106 may deliver theapplication and data file to client 102, for example via an applicationstream to operate in computing environment 15 on client 102, or via aremote-display protocol or otherwise via remote-based or server-basedcomputing. In an embodiment, application delivery system 190 may beimplemented as any portion of the Citrix Workspace Suite™ by CitrixSystems, Inc., such as Citrix Virtual Apps and Desktops (formerlyXenApp® and XenDesktop®).

Policy engine 195 may control and manage the access to, and executionand delivery of, applications. For example, policy engine 195 maydetermine the one or more applications a user or client 102 may accessand/or how the application should be delivered to the user or client102, such as a server-based computing, streaming or delivering theapplication locally to the client 120 for local execution.

For example, in operation, a client 102 may request execution of anapplication (e.g., application 16′) and application delivery system 190of server 106 determines how to execute application 16′, for examplebased upon credentials received from client 102 and a user policyapplied by policy engine 195 associated with the credentials. Forexample, application delivery system 190 may enable client 102 toreceive application-output data generated by execution of theapplication on a server 106, may enable client 102 to execute theapplication locally after receiving the application from server 106, ormay stream the application via network 104 to client 102. For example,in some embodiments, the application may be a server-based or aremote-based application executed on server 106 on behalf of client 102.Server 106 may display output to client 102 using a thin-client orremote-display protocol, such as the Independent Computing Architecture(ICA) protocol by Citrix Systems, Inc. of Fort Lauderdale, Fla. Theapplication may be any application related to real-time datacommunications, such as applications for streaming graphics, streamingvideo and/or audio or other data, delivery of remote desktops orworkspaces or hosted services or applications, for exampleinfrastructure as a service (IaaS), desktop as a service (DaaS),workspace as a service (WaaS), software as a service (SaaS) or platformas a service (PaaS).

One or more of servers 106 may include a performance monitoring serviceor agent 197. In some embodiments, a dedicated one or more servers 106may be employed to perform performance monitoring. Performancemonitoring may be performed using data collection, aggregation,analysis, management and reporting, for example by software, hardware ora combination thereof. Performance monitoring may include one or moreagents for performing monitoring, measurement and data collectionactivities on clients 102 (e.g., client agent 120), servers 106 (e.g.,agent 197) or an appliance 200 and/or 205 (agent not shown). In general,monitoring agents (e.g., 120 and/or 197) execute transparently (e.g., inthe background) to any application and/or user of the device. In someembodiments, monitoring agent 197 includes any of the productembodiments referred to as Citrix Analytics or Citrix ApplicationDelivery Management by Citrix Systems, Inc. of Fort Lauderdale, Fla.

The monitoring agents 120 and 197 may monitor, measure, collect, and/oranalyze data on a predetermined frequency, based upon an occurrence ofgiven event(s), or in real time during operation of network environment100. The monitoring agents may monitor resource consumption and/orperformance of hardware, software, and/or communications resources ofclients 102, networks 104, appliances 200 and/or 205, and/or servers106. For example, network connections such as a transport layerconnection, network latency, bandwidth utilization, end-user responsetimes, application usage and performance, session connections to anapplication, cache usage, memory usage, processor usage, storage usage,database transactions, client and/or server utilization, active users,duration of user activity, application crashes, errors, or hangs, thetime required to log-in to an application, a server, or the applicationdelivery system, and/or other performance conditions and metrics may bemonitored.

The monitoring agents 120 and 197 may provide application performancemanagement for application delivery system 190. For example, based uponone or more monitored performance conditions or metrics, applicationdelivery system 190 may be dynamically adjusted, for exampleperiodically or in real-time, to optimize application delivery byservers 106 to clients 102 based upon network environment performanceand conditions.

In described embodiments, clients 102, servers 106, and appliances 200and 205 may be deployed as and/or executed on any type and form ofcomputing device, such as any desktop computer, laptop computer, ormobile device capable of communication over at least one network andperforming the operations described herein. For example, clients 102,servers 106 and/or appliances 200 and 205 may each correspond to onecomputer, a plurality of computers, or a network of distributedcomputers such as computer 101 shown in FIG. 1C.

As shown in FIG. 1C, computer 101 may include one or more processors103, volatile memory 122 (e.g., RAM), non-volatile memory 128 (e.g., oneor more hard disk drives (HDDs) or other magnetic or optical storagemedia, one or more solid state drives (SSDs) such as a flash drive orother solid state storage media, one or more hybrid magnetic and solidstate drives, and/or one or more virtual storage volumes, such as acloud storage, or a combination of such physical storage volumes andvirtual storage volumes or arrays thereof), user interface (UI) 123, oneor more communications interfaces 118, and communication bus 150. Userinterface 123 may include graphical user interface (GUI) 124 (e.g., atouchscreen, a display, etc.) and one or more input/output (I/O) devices126 (e.g., a mouse, a keyboard, etc.). Non-volatile memory 128 storesoperating system 115, one or more applications 116, and data 117 suchthat, for example, computer instructions of operating system 115 and/orapplications 116 are executed by processor(s) 103 out of volatile memory122. Data may be entered using an input device of GUI 124 or receivedfrom I/O device(s) 126. Various elements of computer 101 may communicatevia communication bus 150. Computer 101 as shown in FIG. 1C is shownmerely as an example, as clients 102, servers 106 and/or appliances 200and 205 may be implemented by any computing or processing environmentand with any type of machine or set of machines that may have suitablehardware and/or software capable of operating as described herein.

Processor(s) 103 may be implemented by one or more programmableprocessors executing one or more computer programs to perform thefunctions of the system. As used herein, the term “processor” describesan electronic circuit that performs a function, an operation, or asequence of operations. The function, operation, or sequence ofoperations may be hard coded into the electronic circuit or soft codedby way of instructions held in a memory device. A “processor” mayperform the function, operation, or sequence of operations using digitalvalues or using analog signals. In some embodiments, the “processor” canbe embodied in one or more application specific integrated circuits(ASICs), microprocessors, digital signal processors, microcontrollers,field programmable gate arrays (FPGAs), programmable logic arrays(PLAs), multi-core processors, or general-purpose computers withassociated memory. The “processor” may be analog, digital ormixed-signal. In some embodiments, the “processor” may be one or morephysical processors or one or more “virtual” (e.g., remotely located or“cloud”) processors.

Communications interfaces 118 may include one or more interfaces toenable computer 101 to access a computer network such as a LAN, a WAN,or the Internet through a variety of wired and/or wireless or cellularconnections.

In described embodiments, a first computing device 101 may execute anapplication on behalf of a user of a client computing device (e.g., aclient 102), may execute a virtual machine, which provides an executionsession within which applications execute on behalf of a user or aclient computing device (e.g., a client 102), such as a hosted desktopsession, may execute a terminal services session to provide a hosteddesktop environment, or may provide access to a computing environmentincluding one or more of: one or more applications, one or more desktopapplications, and one or more desktop sessions in which one or moreapplications may execute.

Additional details of the implementation and operation of networkenvironment 100, clients 102, servers 106, and appliances 200 and 205may be as described in U.S. Pat. No. 9,538,345, issued Jan. 3, 2017 toCitrix Systems, Inc. of Fort Lauderdale, Fla., the teachings of whichare hereby incorporated herein by reference.

B. Appliance Architecture

FIG. 2 shows an example embodiment of appliance 200. As describedherein, appliance 200 may be implemented as a server, gateway, router,switch, bridge or other type of computing or network device. As shown inFIG. 2 , an embodiment of appliance 200 may include a hardware layer 206and a software layer 205 divided into a user space 202 and a kernelspace 204. Hardware layer 206 provides the hardware elements upon whichprograms and services within kernel space 204 and user space 202 areexecuted and allow programs and services within kernel space 204 anduser space 202 to communicate data both internally and externally withrespect to appliance 200. As shown in FIG. 2 , hardware layer 206 mayinclude one or more processing units 262 for executing software programsand services, memory 264 for storing software and data, network ports266 for transmitting and receiving data over a network, and encryptionprocessor 260 for encrypting and decrypting data such as in relation toSecure Socket Layer (SSL) or Transport Layer Security (TLS) processingof data transmitted and received over the network.

An operating system of appliance 200 allocates, manages, or otherwisesegregates the available system memory into kernel space 204 and userspace 202. Kernel space 204 is reserved for running kernel 230,including any device drivers, kernel extensions or other kernel relatedsoftware. As known to those skilled in the art, kernel 230 is the coreof the operating system, and provides access, control, and management ofresources and hardware-related elements of application 104. Kernel space204 may also include a number of network services or processes workingin conjunction with cache manager 232.

Appliance 200 may include one or more network stacks 267, such as aTCP/IP based stack, for communicating with client(s) 102, server(s) 106,network(s) 104, and/or other appliances 200 or 205. For example,appliance 200 may establish and/or terminate one or more transport layerconnections between clients 102 and servers 106. Each network stack 267may include a buffer 243 for queuing one or more network packets fortransmission by appliance 200.

Kernel space 204 may include cache manager 232, packet engine 240,encryption engine 234, policy engine 236 and compression engine 238. Inother words, one or more of processes 232, 240, 234, 236 and 238 run inthe core address space of the operating system of appliance 200, whichmay reduce the number of data transactions to and from the memory and/orcontext switches between kernel mode and user mode, for example sincedata obtained in kernel mode may not need to be passed or copied to auser process, thread or user level data structure.

Cache manager 232 may duplicate original data stored elsewhere or datapreviously computed, generated or transmitted to reducing the accesstime of the data. In some embodiments, the cache memory may be a dataobject in memory 264 of appliance 200, or may be a physical memoryhaving a faster access time than memory 264.

Policy engine 236 may include a statistical engine or otherconfiguration mechanism to allow a user to identify, specify, define orconfigure a caching policy and access, control and management ofobjects, data or content being cached by appliance 200, and define orconfigure security, network traffic, network access, compression orother functions performed by appliance 200.

Encryption engine 234 may process any security related protocol, such asSSL or TLS. For example, encryption engine 234 may encrypt and decryptnetwork packets, or any portion thereof, communicated via appliance 200,may setup or establish SSL, TLS or other secure connections, for examplebetween client 102, server 106, and/or other appliances 200 or 205. Insome embodiments, encryption engine 234 may use a tunneling protocol toprovide a VPN between a client 102 and a server 106. In someembodiments, encryption engine 234 is in communication with encryptionprocessor 260. Compression engine 238 compresses network packetsbi-directionally between clients 102 and servers 106 and/or between oneor more appliances 200.

Packet engine 240 may manage kernel-level processing of packets receivedand transmitted by appliance 200 via network stacks 267 to send andreceive network packets via network ports 266. Packet engine 240 mayoperate in conjunction with encryption engine 234, cache manager 232,policy engine 236 and compression engine 238, for example to performencryption/decryption, traffic management such as request-level contentswitching and request-level cache redirection, and compression anddecompression of data.

User space 202 is a memory area or portion of the operating system usedby user mode applications or programs otherwise running in user mode. Auser mode application may not access kernel space 204 directly and usesservice calls in order to access kernel services. User space 202 mayinclude graphical user interface (GUI) 210, a command line interface(CLI) 212, shell services 214, health monitor 216, and daemon services218. GUI 210 and CLI 212 enable a system administrator or other user tointeract with and control the operation of appliance 200, such as viathe operating system of appliance 200. Shell services 214 include theprograms, services, tasks, processes or executable instructions tosupport interaction with appliance 200 by a user via the GUI 210 and/orCLI 212.

Health monitor 216 monitors, checks, reports and ensures that networksystems are functioning properly and that users are receiving requestedcontent over a network, for example by monitoring activity of appliance200. In some embodiments, health monitor 216 intercepts and inspects anynetwork traffic passed via appliance 200. For example, health monitor216 may interface with one or more of encryption engine 234, cachemanager 232, policy engine 236, compression engine 238, packet engine240, daemon services 218, and shell services 214 to determine a state,status, operating condition, or health of any portion of the appliance200. Further, health monitor 216 may determine if a program, process,service or task is active and currently running, check status, error orhistory logs provided by any program, process, service or task todetermine any condition, status or error with any portion of appliance200. Additionally, health monitor 216 may measure and monitor theperformance of any application, program, process, service, task orthread executing on appliance 200.

Daemon services 218 are programs that run continuously or in thebackground and handle periodic service requests received by appliance200. In some embodiments, a daemon service may forward the requests toother programs or processes, such as another daemon service 218 asappropriate.

As described herein, appliance 200 may relieve servers 106 of much ofthe processing load caused by repeatedly opening and closing transportlayer connections to clients 102 by opening one or more transport layerconnections with each server 106 and maintaining these connections toallow repeated data accesses by clients via the Internet (e.g.,“connection pooling”). To perform connection pooling, appliance 200 maytranslate or multiplex communications by modifying sequence numbers andacknowledgment numbers at the transport layer protocol level (e.g.,“connection multiplexing”). Appliance 200 may also provide switching orload balancing for communications between the client 102 and server 106.

As described herein, each client 102 may include client agent 120 forestablishing and exchanging communications with appliance 200 and/orserver 106 via a network 104. Client 102 may have installed and/orexecute one or more applications that are in communication with network104. Client agent 120 may intercept network communications from anetwork stack used by the one or more applications. For example, clientagent 120 may intercept a network communication at any point in anetwork stack and redirect the network communication to a destinationdesired, managed or controlled by client agent 120, for example tointercept and redirect a transport layer connection to an IP address andport controlled or managed by client agent 120. Thus, client agent 120may transparently intercept any protocol layer below the transportlayer, such as the network layer, and any protocol layer above thetransport layer, such as the session, presentation or applicationlayers. Client agent 120 can interface with the transport layer tosecure, optimize, accelerate, route or load-balance any communicationsprovided via any protocol carried by the transport layer.

In some embodiments, client agent 120 is implemented as an IndependentComputing Architecture (ICA) client developed by Citrix Systems, Inc. ofFort Lauderdale, Fla. Client agent 120 may perform acceleration,streaming, monitoring, and/or other operations. For example, clientagent 120 may accelerate streaming an application from a server 106 to aclient 102. Client agent 120 may also perform end-pointdetection/scanning and collect end-point information about client 102for appliance 200 and/or server 106. Appliance 200 and/or server 106 mayuse the collected information to determine and provide access,authentication and authorization control of the client's connection tonetwork 104. For example, client agent 120 may identify and determineone or more client-side attributes, such as: the operating system and/ora version of an operating system, a service pack of the operatingsystem, a running service, a running process, a file, presence orversions of various applications of the client, such as antivirus,firewall, security, and/or other software.

Additional details of the implementation and operation of appliance 200may be as described in U.S. Pat. No. 9,538,345, issued Jan. 3, 2017 toCitrix Systems, Inc. of Fort Lauderdale, Fla., the teachings of whichare hereby incorporated herein by reference.

C. Systems and Methods for Preventing Unauthorized Access to Informationfrom a Resource

The systems and methods presented herein include a novel approach forpreventing unauthorized access, retrieval, storage, and/or usage ofinformation from one or more resources (e.g., via URLs in requests). Thenovel approach includes one or more mechanisms to validate, confirm,and/or verify whether a request/message (e.g., a HTTP REQUEST URL) toaccess a resource (e.g., via a URL) is a valid request. Therefore, thenovel approach may prevent random, unauthorized, and/or malicious accessto information (e.g., pricing information) from a resource (e.g., a webserver/service). Compared to present technology, certain embodiments ofthe systems and methods presented herein (e.g., encryption-basedapproaches) may reduce/decrease memory usage by at least 35% (e.g., 45,55 or other percent) for instance, by relying on more processingresource for example. Other embodiments (e.g., hash-based approaches)may increase processing efficiency (e.g., CPU efficiency) by at least25% (e.g., 35, 45 or other percent) for example, by relying on morememory usage for instance.

The present disclosure is directed towards systems and methods forpreventing malicious entities and/or bots from gaining unauthorizedaccess to information from a resource/service by obfuscating and/orrandomizing each URL in a response from the server (e.g., HTTPRESPONSE). For instance, a device (e.g., a gateway module, alocal/foreign node, network appliance and/or an application deliverycontroller (ADC)) intermediary between a client and a server mayreceive, obtain, and/or process a first request from the client (e.g., asmartphone, a laptop, a tablet device, a desktop computer of a user,and/or a client supporting HTTP/HTTPS). Responsive to receiving thefirst request/message (e.g., HTTP GET, GET /index.html, and/or otherrequests), the device may create, generate, configure, and/or establisha session between the client and the server. In some embodiments, thedevice may create, generate, configure, establish, and/or assign aunique client identifier (e.g., CLIENT_SESSION_ID and/or CLIENT_PCK) forthe client and/or at least one key of the device (e.g., ENC_KEY). Insome embodiments, the device may create and/or assign the clientidentifier and/or the key(s) responsive to receiving the first request.In some embodiments, the key(s) may include or correspond to a tokenand/or other information that is preconfigured across one or moredevices in a system (e.g., a distributed system). The key(s) may bevalid/active for a configured and/or predetermined time interval or timeinstance. The key(s) can be updated and/or adjusted across one or moretime instances and/or time intervals. In some embodiments, the key(s)can be used, accessed, shared, and/or stored by one or more devices(e.g., one or more ADCs) of a system.

In some embodiments, the first request (e.g., an HTTP GET request and/orother requests) may include, provide, specify, and/or indicate a firstURL to access a first resource of the server (e.g., a resource, service,and/or application hosted on the server). Responsive to receiving and/orobtaining the first request, the device may forward, send, communicate,transmit, and/or broadcast the first request to the server. Uponreceiving the first request, the server may send, transmit, and/orcommunicate a response (e.g., an HTTP response) to the device, whereinthe response can include, specify, and/or indicate one or more resources(e.g., HTTP RESPONSE URLs). In some embodiments, the device may process,parse, analyze, and/or evaluate the received response (e.g., HTTPRESPONSE) to identify, for instance, each of the URLs (e.g., secondURLs) in the response. For each URL in the response, the device canobfuscate, obscure, hide, and/or randomize the URL into a string (e.g.,a hash value and/or an encrypted version of the URL). Responsive toobfuscating the URL(s), the device may update and/or modify the responseby replacing each URL with a corresponding string (e.g., an obfuscatedversion of the URL), so that the client or any entity intercepting theresponse/string would not be able to determine or extract path, folderor directory structure information embedded/incorporated in the URL orinferable from the URL, for instance.

In some embodiments, the device may update and/or adjust the response byincluding the client identifier in a set-cookie field (e.g., performinga set-cookie command with the client identifier). By including theclient identifier in a set-cookie field, subsequent requests from theclient to access a resource may include, provide, specify, and/orindicate a cookie (e.g., a HTTP cookie configured by the set-cookiecommand), wherein the cookie can include or correspond to the clientidentifier. Responsive to updating the received response from theserver, the device may send, transmit, forward, and/or communicate theresponse to the client. The response may include, provide, specify,and/or indicate the modified/updated URL(s), the client identifier,and/or other information.

In some embodiments, the device may receive a subsequent request (e.g.,a second request) that includes a third URL and/or a candidate clientidentifier. The device may extract, obtain, acquire, and/or use thecandidate client identifier from the subsequent request (e.g., from theHTTP REQUEST HEADER or cookie information/field of the subsequentrequest). In some embodiments, the device may validate, verify, and/orconfirm the candidate client identifier of the subsequent request. Forexample, the device may compare the candidate client identifier with theclient identifier assigned, generated, and/or maintained by the device.If the candidate client identifier corresponds to (e.g., matches or iswithin a defined range/extent of) the client identifier of the device,the device may proceed with determining whether at least one URL (e.g.,a second URL) from the response is recoverable using the third URL. Forinstance, the device may determine whether the at least one URL isrecoverable by determining whether the third URL is included in amapping data (e.g., URL MAPPING DATA) as a string (e.g., a hash value).In another example, the device may determine whether the at least oneURL is recoverable by performing decryption of the third URL based on anencryption key (e.g., calculated according to the candidate clientidentifier and/or the key of the device). If the at least one URL isrecoverable (e.g., subsequent request is valid), the device may replacethe third URL in the subsequent request with the recovered URL and/orallow the server to receive the subsequent request. Otherwise (e.g.,subsequent request is invalid), the device may determine to preventand/or preclude the server from receiving the subsequent request (e.g.,the device may drop the subsequent request).

In view of the above discussion regarding preventing unauthorized accessof resource information, a process and/or system for performing saidprevention (e.g., via a client identifier and/or obfuscation of a URL)may be beneficial, as further explained in the following passages.Referring to FIG. 3 , depicted is a block diagram of one exampleembodiment of a system 300 for preventing unauthorized access,retrieval, storage, and/or usage of information from a resource. Thesystem 300 may include one or more clients 102 of an entity (e.g., anorganization or a corporate entity), one or more devices 302, and/or oneor more servers 106 hosting one or more resources 304. The device 302can include or maintain or have access to at least one client identifier306(1). The client 102 can include or maintain or have access to atleast one candidate client identifier 306(2).

Each of the above-mentioned elements or entities is implemented inhardware, or a combination of hardware and software, in one or moreembodiments. Each component of the system 300 may be implemented usinghardware or a combination of hardware or software detailed above inconnection with FIG. 1C. For instance, each of these elements orentities can include any application, program, library, script, task,service, process or any type and form of executable instructionsexecuting on hardware of a client device 102, a server 106 and/or anetwork device 200 in connection with FIGS. 1B-1C, for instance. Thehardware includes circuitry such as one or more processors in one ormore embodiments.

The system 300 may include one or more servers 106. The server 106(e.g., a back-end server supporting HTTPS messages or transactions,and/or other servers 106) may be configured and/or designed to host oneor more resources 304 (e.g., one or more URLs) and/or services (e.g.,application resources, as a web application, SaaS application orremote-hosted network application). The server 106 may be configuredand/or designed to provision the one or more resources 304 and/orservices to one or more clients 102 of a consumer or other entity (e.g.,an organization or user), via one or more networks 104. For example, theclient 102 may establish one or more sessions or connections (e.g.,secured or otherwise, such as a SSL virtual private network connection)with the server(s) 106 to access a service/resource 304 (e.g., via oneor more URLs), such as an application resource. In another example, theserver(s) 106 may receive/obtain a request (e.g., a first/secondrequest, such as a HTTP request) from the client 102 (e.g., via a device302) to access/use one or more resources 304 (or establish theconnections to access the one or more resources 304). The server(s) 106may receive/obtain a first URL and/or other information via the request.For example, a first request may include, specify, indicate, and/orprovide the first URL and/or other information.

Responsive to receiving the request(s), the server(s) 106 may send,transmit, and/or communicate a response to the client 102 via the device302. The server(s) 106 may provide, indicate, and/or specify one or moreURLs (e.g. one or more second URLs) and/or other information via theresponse. For example, the response from the server(s) 106 may indicateand/or include one or more second URLs to access one or more resources304. The one or more second URLs may be associated and/or mapped to thefirst URL of the request (e.g., first request) received by the server106. For instance, the first URL can be a parent URL to each of thesecond URLs in the response from the server 106.

In some embodiments, the server(s) 106 can be part of a cloud ordatacenter for instance. The server(s) 106 may include any embodiment ofvolatile memory 122 or non-volatile memory 128 (discussed in FIG. 1C forexample) which may store files, data and/or content of the service. Theserver(s) 106 may communicate with other various components of thesystem 300 in FIG. 3 via a communications interface 118 for instance.Hence, the server(s) 106 may be similar in some aspects to the computer101 described with reference to FIG. 1C.

To provide a service/resource 304, the server(s) 106 may execute,provide, provision, and/or host one or more network application(s). Insome embodiments, a service/resource 304 may be referred tointerchangeably with an application, application resource or networkapplication. A network application can for instance include aremote-hosted application, a remote-hosted desktop, a web application ora software-as-a-service (SaaS) application. A remote-hosted desktop maybe a virtual desktop hosted on the server 106 which is accessed by orremotely provisioned to the client 102. In some embodiments, thedelivery of a remote-hosted desktop may be via a session and/orconnection based on High-Definition User Experience (HDX) or IndependentComputing Architecture (ICA) display remoting protocol, or RemoteDesktop Protocol (RDP). A remote-hosted application mayinclude/correspond to an application service that can be delivered via aHDX-based, ICA-based, RDP-based, etc., session and/or connection. Insome embodiments, a remote-hosted application may be an applicationwhich is installed on/in the remote-hosted desktop environment and istherefore accessible within the remote-hosted desktop. A SaaSapplication can be a centrally-hosted application which is typicallyaccessible on a subscription basis. In some embodiments, the SaaSapplications may include web-based applications. In other embodiments,the SaaS applications may correspond to remote-hosted applications and,therefore, can be delivered in HDX/ICA/RDP-based sessions and/orconnections. SaaS applications and/or web applications may include forinstance salesforce.com, SAP, Microsoft Office 365, Dropbox or Gmailservice, Amazon web services, and so on.

The system 300 may include one or more clients 102. The client 102 mayinclude or correspond to devices of a consumer of the service. Forexample, if the consumer is an individual or user, the client 102 maycomprise a smartphone, a laptop (e.g., at home), a tablet device, and adesktop computer (e.g., at work), that the user may use to access anapplication resource (e.g., Dropbox service) and/or other resources 304at various times and/or locations for instance. In an example where theconsumer is an organization, such as an enterprise, the consumer canextend over a number of users (e.g., management persons, staff members,IT administrators, and so on) and their associated client(s) 102 ordevices (e.g., corporate-issued device, personally-owned devices, and/orregistered/approved devices (e.g., in a BYOD program)). Any number ofthe users may access a service/resource 304 (e.g., salesforce.com, SAP,Microsoft Office 365) from a service/resource 304 provider, via acorporate account for the service/resource 304 for instance.

The client 102 may be configured and/or designed to access one or moreapplication resource(s) 304 over one or more networks. In someembodiments, the client 102 may interact with the server(s) 106 via adevice 302 (e.g., a device 302 intermediary between the client 102 andthe server(s) 106). For example, the client 102 may send a request(e.g., a first request, a second request, and/or other requests toaccess/use a resource 304) and/or message (e.g. a HTTP message and/orother messages) to the server(s) 106 via the device 302.

The request may include and/or specify a URL (e.g., a first URL) of theserver(s) 106. As such, the request may include or correspond to arequest to access/use/traverse the URL of the request, and/or obtaininformation from the resource associated with the URL. Responsive tosending the request/message, the client 102 may receive/obtain aresponse from the server 106 and/or a device 302 (e.g., an ADC and/orother devices). For example, responsive to receiving a request, theserver 106 may send a response to the client 102 via the device 302. Theresponse may include one or more URLs (e.g., second URLs) and/or otherinformation. The device 302 may obfuscate some aspects (e.g., URLs) ofthe response. In some embodiments, the client 102 may receive one ormore URLs (e.g., obfuscated second URLs) and/or a client identifier306(1) via the response from the device 302. As discussed herein,references to a resource may sometimes refer to anidentification/indication/indicator of the resource (e.g., as a uniformresource indicator), and may sometimes refer to the resource itself. Insome embodiments, the client 102 may send a second request directed tothe server 106 (via the device 302) that includes the one or moreobfuscated URLs from the server response. The second request (e.g., HTTPGET request) may include and/or provide at least one URL of the URLsfrom the server response (e.g., a third URL), and/or a candidate clientidentifier 306(2). The at least one URL of the second request mayinclude or correspond to a second URL from the response obfuscated intoa string (e.g., a hash value and/or an encrypted version of the URL).

The system 300 may include one or more devices 302 (sometimes referredto as appliance(s) 200, gateway(s) 200, node(s), and/or applicationdelivery controllers). A device 302 may be configured and/or designed toserve as an intermediary between different elements of a computer and/ornetwork environment, such as between client(s) 102, server(s) 106,network(s) 104, and/or other devices 302 (e.g., as discussed above inconnection with FIG. 2 ). In some embodiments, the device 302 mayreceive/obtain a first request/message (e.g., HTTP GET request and/orother requests) from a client 102 and/or user to access one or moreresources 304 from the server 106. The first request may include,provide, and/or specify a first URL for accessing a resource 304 and/orinformation from a resource 304. Responsive to receiving therequest/message, the device 302 may create, generate, and/or establish asession between the client 102 and the server 106. The device 302 maygenerate, configure, and/or assign a client identifier 306(1) (e.g.,CLIENT_SESSION_ID and/or CLIENT_PCK) for the client 102 and/or a key ofthe device 302. The device 302 may store and/or maintain the clientidentifier 306(1) and/or the key of the device 302. The clientidentifier 306(1) may include or correspond to a client ID, a clienttoken and/or other information that uniquely identifies the client 102,the session, and/or the details of the session (e.g.,messages/requests/resources exchanged during a session). The clientidentifier 306(1) and/or the session may be valid for aconfigured/predetermined timeout or expiration interval/instance. Thesession and/or client identifier 306(1) may be used to track/monitor theresources 304 accessed/used by the client 102.

In some embodiments, the device 302 may send, forward, and/or route thefirst request to the server 106. Responsive to sending/transmitting thefirst request, the device 302 may receive a response from the server106. The device 302 may parse, analyze, and/or evaluate the responsefrom the server 106 to obtain, extract, and/or acquire one or moresecond URLs from the response. For each second URL in the response, thedevice 302 may obfuscate and/or obscure the second URL into a string(e.g., to remove path/folder/directory information in or obtainable fromthe second URL). For instance, the device 302 may obfuscate each of thesecond URL(s) into a corresponding/unique string by applying a hashfunction on a combination of a unique URL identifier (e.g., generated bythe device 302 for each second URL), the client identifier 306(1),and/or a domain name of the server 106 (e.g., SHA_MODIFIED_HTTP_URL=SHA{UNIQUE_URL_NUMBER, DOMAIN_NAME, CLIENT_SESSION_ID}). As such, eachparticular string can be unique/specific to a particular resource 304(e.g., the resource indicated by the second URL) hosted by the server106 with the domain name, and/or to the session and/or the client. Inanother example, the device 302 may obfuscate the second URL(s) into acorresponding/unique string by performing encryption of the second URLusing a first encryption key (e.g., encrypt (second URL, firstencryption key)). The device 302 may determine and/or generate the firstencryption key according to (e.g., by combining and/or appending) thekey of the device 302 and/or the client identifier 306(1) (e.g.,ENCRYPTION_KEY={ENC_KEY, CLIENT_PCK}). In some embodiments, the device302 may update, adjust, and/or modify the response by including theclient identifier 306(1) in a set-cookie field (e.g., set-cookie HTTPheader). In certain embodiments, the device 302 may update the responseby adding, incorporating, replacing, and/or exchanging the second URL(s)from the response with a corresponding string (e.g., an obfuscatedversion of the second URL). Responsive to updating the response, thedevice 302 may forward/send the updated response to the client 102.

In some embodiments, the device 302 may receive another request (e.g., asecond request) from a client 102 and/or user. The second request mayinclude, indicate, and/or specify at least one URL, such as a third URL(e.g., an obfuscated URL), to the device 302. The device 302 may receiveand/or obtain a candidate client identifier 306(2) (e.g., in cookieinformation/field of the second request), the third URL, and/or otherinformation via the second request (e.g., the second request can includea candidate client identifier 306(2) and/or the third URL). The device302 may extract, acquire, determine, and/or identify the candidateclient identifier 306(2) and/or the third URL from the second request.Responsive to extracting the candidate client identifier 306(2) (orother information), the device 302 may validate, confirm, and/or verifythe candidate client identifier 306(2). For example, the device 302 maydetermine whether the candidate client identifier 306(2) corresponds to(e.g., matches or is within a defined range/extent of) the clientidentifier 306(1) generated and/or maintained by the device 302. If thecandidate client identifier 306(2) fails to correspond to the clientidentifier 306(1), the device 302 may determine that the second requestis invalid, and therefore may prevent the server 106 from receiving thesecond request with the third URL (e.g., the device 302 may drop/blockthe second request). If, on the other hand, the candidate clientidentifier 306(2) corresponds to the client identifier 306(1), thedevice 302 may proceed with determining whether at least one second URLfrom the response is recoverable/retrievable using the third URL.

In some embodiments, the device 302 may determine whether at least onesecond URL is recoverable by determining whether the obfuscated thirdURL (e.g., a hash value and/or an encrypted URL) is in a mapping data(e.g., whether the third URL is mapped to or corresponds to at least onesecond URL). The mapping data can indicate and/or specify amapping/association/relationship between a second URL from the responseand a corresponding string (e.g., a hash value). In another example, thedevice 302 may determine whether at least one second URL is recoverableby performing a decryption or decoding of the third URL using a secondencryption key (e.g., generated by the device 302 using the candidateclient identifier 306(2) and/or the key of the device 302). If, forexample, the performed decryption fails (e.g., the device 302 is unableto decrypt the third URL using the second encryption key, or tosuccessfully perform or complete the decryption), the second URL may beunrecoverable using the third URL. If the device 302 determines that thesecond URL is recoverable, the device 302 may update, adjust, and/ormodify the second request by replacing the third URL (e.g., anobfuscated URL) with the recovered second URL (e.g., an original URL,prior to obfuscation). Responsive to updating the second request, thedevice 302 may determine to allow the server 106 to receive the updatedsecond request (e.g., the client 102 can access, use, and/or traversethe resource 304 associated to the third URL). If, instead, the device302 determines that the second URL is unrecoverable, the device 302 mayprevent the server 106 from receiving the second request (e.g., thedevice 302 may determine the request is malicious and/or potentiallymalicious). By dropping or blocking the second request from reaching theserver 106, the device 302 can prevent a client 102 (e.g., a potentialattacker) from accessing, using, and/or traversing a resource 304 and/orinformation from the resource 304 associated with the third URLindicated in the second request.

In some embodiments, the device 302 may be located at any one of variouspoints or in any of various communication paths, for example between twonetworks 104, within a computing and/or network environment 100. Inother embodiments, the device 302 may be located on a network 104. Oneor more devices 302 may communicate with one another and/or work inconjunction to, for example, accelerate, protect and/or secure networktraffic between clients 102 and servers 106 and/or provide loadbalancing of servers 106 to process requests from clients 102. In someembodiments, the one or more devices 302 may act as a proxy or accessserver to provide access to the one or more servers 106, providesecurity and/or act as a firewall between the client 102 and the server106, and/or provide a secure VPN connection from the client 102 to theserver 106, such as a SSL VPN connection and/or provide encryption anddecryption operations.

In some embodiments, the device 302 and/or the client 102 can include,among other elements, one or more client identifiers 306, such as agenerated client identifier 306(1) and/or a candidate client identifier306(2). The client identifier 306(1) generated by the device 302 may beconfigured and/or designed to uniquely identify or map to the client102, the session (e.g., a session between a client 102 and a server106), and/or the details of the session (e.g.,messages/requests/resources exchanged during a session). In someembodiments, the client identifier 306(1) and/or the candidate clientidentifier 306(2) may include or correspond to a token and/or otherinformation that uniquely identifies the client 102. In someembodiments, the client identifier 306(1) may be valid/active for aconfigured and/or predetermined time interval or time instance. Theclient identifier 306 may be used to track/monitor the resources (e.g.,HTTPS URLs) accessed, used, and/or visited by the client 102 during thesession. In some embodiments, the client identifier 306(1) can be used,accessed, and/or stored by one or more devices 302 (e.g., one or moreADCs) of a system (e.g., a distributed system). In some embodiments, theclient identifier 306(1) and/or the candidate client identifier 306(2)can be used to perform a primary authentication (e.g., a first levelcheck) of a request to access a resource 304. For instance, a candidateclient identifier 306(2) can be compared with the client identifier306(1) assigned by a device 302 (e.g., assigned to a client 102), inorder to determine whether the request is a malicious attempt to accessa resource 304. If the candidate client identifier 306(2) fails to match(e.g., is not consistent with, or conflicts with) the client identifier306(1) assigned by the device 302, the device 302 may determine toprevent the server 106 from accessing the resource 304 and/orinformation from the resource. In some embodiments, the clientidentifier(s) 306 may be stored/maintained in a cache of the device 302,a memory 264 of the device 302, and/or a physical memory having a fasteraccess time than memory 264. The client identifier(s) 306 may belocated/maintained within or apart from the device 302.

Referring now to FIG. 4 , depicted is a communication diagram of anembodiment of a process 400 for preventing unauthorized access,retrieval, storage, and/or usage of information from a resource. Inaccordance with process 400, the client 102 may send, transmit, and/orcommunicate a first request/message (e.g., HTTP GET, GET /index.html,and/or other requests) to the server 106 via the device 302 (402). Thefirst request (e.g., HTTP REQUEST) may include a first URL (e.g.,/index.html and/or other resources) of the server 106 and/or otherinformation. Responsive to receiving and/or obtaining the first requestfrom the client 102, the device 302 may create, generate, configure,establish and/or assign a unique/new client identifier 306(1) (e.g.,CLIENT_SESSION_ID, a client token, and/or other information) for theclient 102 (404), in some embodiments. The client identifier 306(1) maybe used to track and/or monitor the resource(s) 304 (e.g., HTTP URLs)accessed by the client 102 during a session. For instance, during asession, the client identifier 306(1) can be used to identify/update arepository (or other storage) and/or history of resources 304 accessedby the client 102. In some embodiments, the client identifier 306(1) canbe used to generate, create, compute, and/or calculate a unique string(e.g., a hash value) for at least one URL (e.g., a second URL). In someembodiments, the client identifier 306(1) may be used to determinewhether a received request (e.g., a second request to access a resource304) is valid. The device 302 may store and/or maintain the clientidentifier 306(1) in the data/information of the session.

In some embodiments, the device 302 may forward, send, route, and/orcommunicate the first request (e.g., GET /index.html) to the server 106(406). The server 106 may receive and/or obtain the first request (e.g.,a request to access a first resource 304(1)) from the device 302 (406)and/or send/transmit a response (e.g., response for index.html and/orother HTTP responses) to the device 302 (408). The response from theserver 106 may include, provide, and/or specify one or more second URLsand/or other information. Responsive to receiving the response from theserver 106, the device 302 may parse, analyze, and/or evaluate theresponse (e.g., HTTP response page) from the server 106 (e.g., toidentify each second URL). For each second URL in the server response,the device 302 may generate, determine, and/or assign a unique URLidentifier (e.g., UNIQUE_URL_NUMBER) (410). The unique URL identifier(s)can be accessed and/or shared by one or more clients 102 acrosssessions. Responsive to determining the URL identifier(s), the device302 may append, combine, and/or incorporate the client identifier 306(1)with the URL identifier(s). The device 302 may use the URLidentifier(s), combined with the client identifier 306(1), to determinea string for each second URL (to use to obfuscate information in thesecond URL), such as a hash value (e.g., a cryptographic hash value)(412). For example, the device 302 may determine and/or generate thestring (e.g., SHA_MODIFIED_HTTP_URL) by applying and/or using a hashfunction (e.g., secure hash algorithm (SHA) function and/or other hashfunctions) on a combination of the URL identifier(s), the clientidentifier 306(s), and/or a domain name of the server 106 (or otheraddresses). The string(s) can be unique and/or valid to a particularclient 102 (e.g., the client 102 sending the first request) and/orsession (e.g., a session between the client 102 and the server 106).

Once the device 302 generates/determines the string(s), the device 302can create, determine, generate, configure, store, and/or maintain amapping and/or association (e.g., URL MAPPING) between each string and acorresponding second URL (414). The mapping can indicate a particularstring is associated, mapped, and/or related to a specific URL (e.g.,second URL). As such, each particular string included in the mapping canbe used (e.g., by a client 102 and/or a device 302) to specify,indicate, and/or identify a particular URL (e.g., a second URL from theresponse). The device 302 may store and/or maintain the mapping inmapping data for the session (e.g., particular to the session and/orclient 102).

In some embodiments, the device 302 can update, modify, and/or adjustthe received response from the server 106 (416). For example, the device302 may update the response by replacing, substituting, exchanging,swapping, and/or switching each second URL with a corresponding string(e.g., hash value calculated based on a combination of the unique URLidentifier, the client identifier 306(1), and/or the domain name of theserver 106). By replacing each second URL with the corresponding string,the device 302 may obfuscate the second URL(s) into the string(s),thereby making the original second URL(s) inaccessible or unavailable tothe client 102 (or a bot) to read/parse. In addition to modifying eachsecond URL, the device 302 may further update the response by includingand/or incorporating the client identifier 306(1) (and/or otherinformation) in a set-cookie field (e.g., a set-cookie HTTP header) ofthe response. For instance, the device 302 may perform a set-cookiecommand with the client identifier 306(1). As such, subsequent requeststo access a resource 304 can provide, specify, and/or indicate acandidate client identifier 306(2) (e.g., an HTTP cookieCLIENT_SESSION_ID).

In some embodiments, the device 302 may send, forward, transmit, route,and/or communicate the updated/modified response from the server 106(e.g., the response including the modified second URL(s) and/or theclient identifier 306(1)) to the client 102 (418). Responsive toreceiving the updated response, the client 102 may send or transmit asecond request (e.g., GET request and/or other requests) to the server106 via the device 302 within the session (420). The second request mayinclude, indicate, and/or specify a third URL (e.g., obfuscated into acorresponding string), a candidate client identifier 306(2) and/or otherinformation. The second request may include or correspond to a requestto access and/or use a resource 304 of the server 106. In someembodiments, the device 302 may extract the candidate client identifier306(2) (e.g., included in a HTTP REQUEST HEADER as a cookie of thesecond request) to determine whether the candidate client identifier306(2) (provided by the client 102, e.g., as a cookie) is valid (e.g.,whether the candidate client identifier 306(2) matches or corresponds tothe client identifier 306(1) stored/calculated by the device 302) (422).If the device 302 determines the candidate client identifier 306(2) ofthe second request is invalid, the device 302 may drop the secondrequest, and therefore prevent/preclude the server 106 from receivingthe second request. Otherwise (e.g., if the candidate client identifier306(2) is valid), the device 302 may proceed with step 424 of process400.

Responsive to receiving and/or obtaining the second request, and/orresponsive to determining the candidate client identifier 306(2) isvalid, the device 302 may extract, obtain, check, retrieve, and/oracquire the mapping from the mapping data for the session (424). Oncethe device 302 retrieves the mapping, the device 302 may determinewhether at least one second URL (from the server response) isrecoverable/retrievable based on (or by using) the third URL of thesecond request. For instance, the device 302 may determine whether themapping includes the third URL (e.g., whether the mapping includes astring corresponding to (or associated with) the third URL) (426). Ifthe mapping includes the third URL, at least one second URL from theresponse is recoverable according to the third URL (e.g., the secondrequest is valid). As such, the device 302 can extract, obtain,identify, and/or determine the at least one second URL from the mapping,according to the third URL (428). For instance, the device 302 maydetermine the at least one second URL from the mapping by identifyingthe second URL associated with (mapping to) the third URL. In someembodiments, the device 302 may update, change, and/or modify the secondrequest by replacing the third URL in the request (e.g., an obfuscatedURL) with the recovered second URL (e.g., determined from the mapping)(430). The device 302 may allow the server 106 to receive the secondrequest by forwarding, sending, transmitting, and/or routing the secondrequest to the server 106 (432).

Referring now to FIG. 5 , depicted is a communication diagram of anembodiment of a process 500 for preventing unauthorized access,retrieval, storage, and/or usage of information from a resource. Inaccordance with process 500, the client 102 may send, transmit, and/orcommunicate a first request/message (e.g., HTTP GET, GET /index.html,and/or other requests) to the server 106 via the device 302 (502). Thefirst request (e.g., HTTP REQUEST) may include a first URL (e.g.,/index.html and/or other resources) of the server 106 and/or otherinformation. Responsive to receiving and/or obtaining the first requestfrom the client 102, the device 302 may create, generate, configure,and/or establish a key of the device 302 (e.g., ENC_KEY) (504), in someembodiments. The key of the device 302 can be shared, accessed, and/orused by one or more devices in a system (e.g., distributed system). Insome embodiments, the device 302 may create and/or generate a uniquesession ID for the client 102 (e.g., CLIENT_SESSION_ID) (506) and/or aunique client identifier 306(1) (e.g., CLIENT_PCK) for the session(508). In some embodiments, the client identifier 306(1) and/or the keyof the device 302 can be used (e.g., by the device 302) to generate,create, compute, and/or calculate a first encryption key to performencryption (e.g., perform encryption of a second URL). In someembodiments, the client identifier 306(1) may be used to determinewhether a received request (e.g., a second request to access a resource304) is valid. The device 302 may store and/or maintain the clientidentifier 306(1) in the data/information of the session.

In some embodiments, the device 302 may forward, send, route, and/orcommunicate the first request (e.g., GET /index.html) to the server 106(510). The server 106 may receive and/or obtain the first request (e.g.,a request to access a first resource 304(1)) from the device 302 (510)and/or send/transmit a response (e.g., response for index.html and/orother HTTP responses) to the device 302 (512). The response from theserver 106 may include, provide, and/or specify one or more second URLsand/or other information. Responsive to receiving the response from theserver 106, the device 302 may parse, analyze, and/or evaluate theresponse (e.g., HTTP response page) from the server 106 (e.g., toidentify each second URL). In some embodiments, the device 302 maygenerate, determine, and/or configure a first encryption key using theclient identifier 306(1) and/or the key of the device 302 (514). Forexample, the device 302 may determine the first encryption key byappending, adding, combining, and/or incorporating the client identifier306(1) to the key of the device 302 (e.g., ENCRYPTION_KEY={ENC_KEY,CLIENT_PCK}). For each second URL in the response, the device 302 maygenerate a string by performing encryption using the second URL(s) andthe first encryption key (516). For instance, the device 302 cangenerate the string(s) by encrypting each second URL according to (or byusing) the first encryption key (e.g., encrypt (second URL, firstencryption key)). The string(s) can be unique and/or valid to aparticular client 102 (e.g., the client 102 sending the first request)and/or session (e.g., a session between the client 102 and the server106).

Once the device 302 generates/determines the string(s), the device 302can update, modify, and/or adjust the received response from the server106 (518). For example, the device 302 may update the response byreplacing each second URL with a corresponding string (e.g., anencrypted version of each second URL). By replacing each second URL withthe corresponding string, the device 302 may obfuscate the second URL(s)into the string(s), thereby making the original second URL(s)inaccessible or unavailable to the client 102 (or a bot) to parse/read(the second URL's information on path/folder/directory). In addition tomodifying each second URL, the device 302 may further update theresponse by including and/or incorporating the client identifier 306(1)(and/or other information) in a set-cookie field (e.g., a set-cookieHTTP header) of the response. For instance, the device 302 may perform aset-cookie command with the client identifier 306(1). As such,subsequent requests to access a resource 304 can provide, specify,and/or indicate a candidate client identifier 306(2) (e.g., an HTTPcookie CLIENT_PCK), in the requests' cookie information.

In some embodiments, the device 302 may send, forward, transmit, route,and/or communicate the updated/modified response from the server 106(e.g., the response including the modified second URL(s) and/or theclient identifier 306(1)) to the client 102 (520). Responsive toreceiving the updated response, the client 102 may send, transmit,and/or broadcast a second request (e.g., GET request and/or otherrequests) to the server 106 via the device 302 within the session (522).The second request may include, indicate, and/or specify a third URL(e.g., obfuscated into a corresponding string), a candidate clientidentifier 306(2) and/or other information. In some embodiments, thedevice 302 may extract the candidate client identifier 306(2) (e.g.,included in a HTTP REQUEST HEADER as a cookie of the second request) todetermine whether the candidate client identifier 306(2) (provided bythe client 102, e.g., as a cookie) is valid (e.g., whether the candidateclient identifier 306(2) matches or corresponds to the client identifier306(1) stored/calculated by the device 302) (524). If the device 302determines the candidate client identifier 306(2) of the second requestis invalid, the device 302 may drop the second request, and thereforeprevent/preclude the server 106 from receiving the second request.Otherwise (e.g., if the candidate client identifier 306(2) of the secondrequest is valid), the device 302 may proceed with step 526 of process500.

Responsive to receiving and/or obtaining the second request, and/orresponsive to determining the candidate client identifier 306(2) isvalid, the device 302 may generate, configure, and/or determine a secondencryption key using the candidate client identifier 306(2) and/or thekey of the device 302 (526). For instance, the device may determine thesecond encryption key by appending and/or combining the candidate clientidentifier 306(2) and/or the key of the device 302. Once the device 302determines/generates the second encryption key, the device 302 maydetermine whether at least one second URL (from the server response) isrecoverable/retrievable based on (or by using) the third URL (e.g., anencrypted URL) of the second request. For instance, the device 302 mayperform decryption of the third URL using the second encryption key, todetermine whether the at least one second URL is recoverable (528). Afailure of the decryption can be indicative that the at least one secondURL is unrecoverable using the third URL (e.g., the second request isinvalid). In one example, a failure of the decryption can occur if thethird URL is encrypted according to another key of the device 302 (e.g.,a stale and/or expired key). As such, the device 302 may drop the secondrequest responsive to a failure of the decryption (e.g., to prevent theserver 106 from receiving the request). If, for example, the decryptionof the third URL (e.g., using the second encryption key) is successful,the at least one second URL is recoverable according to the third URL(e.g., the second request is valid). For instance, a decrypted third URLmay include or correspond to at least one second URL from the response,and as such, the at least one second URL is recoverable using the thirdURL. In some embodiments, the device 302 may update, change, and/ormodify the second request by replacing the third URL in the secondrequest (e.g., an obfuscated URL) with the recovered second URL (e.g.,determined according to the decryption) (530). The device 302 may allowthe server 106 to receive the second request by forwarding, sending,transmitting, and/or routing the second request to the server 106 (532).

Referring to FIG. 6 , depicted is a flow diagram of one embodiment of amethod for preventing unauthorized access, retrieval, storage, and/orusage of information from a resource. The functionalities of the methodmay be implemented using, or performed by, the components detailedherein in connection with FIGS. 1-5 . In brief overview, a device 302may receive a first request from the client that includes a firstuniform resource locator (URL) of the server (602). The device 302 mayreceive a response from the server 106 (604). The device 302 may updatethe response using a client identifier 306(1) (606). The device 302 mayreceive a second request with a candidate client identifier 306(2)(608). The device 302 may determine whether the client identifier 306(1)matches the candidate client identifier 306(2) of the second request(610). The device 302 may determine the second request is invalid (612).The device 302 may determine whether a second URL is recoverable (614).The device 302 may update the second request using the recovered secondURL (616). The device 302 may allow the server 106 to receive theupdated second request (618).

Referring now to operation (602), and in some embodiments, a device 302(e.g., an ADC and/or other devices) in a session may receive and/orobtain a first request (e.g., HTTP GET REQUEST) from the client 102. Thefirst request may include, provide, and/or specify a first URL of theserver 106 and/or other information. In some embodiments, the firstrequest may include or correspond to a request to access and/or traversea first resource 304 of the server 106. Referring now to operation(604), and in some embodiments, the device 302 may receive a responsefrom the server 106. For instance, responsive to receiving the firstrequest, the server 106 may determine one or more second URLs associatedto the first URL of the first request. In one example, the first URL canbe a parent URL to the one or more second URLs. Upon determining the oneor more second URLs, the server 106 may send, transmit, and/orcommunicate a response to the device 302. The response may include,provide, and/or indicate the one or more second URLs and/or otherinformation of the resources associated to the URLs.

Referring now to operation (606), and in some embodiments, the device302 may update, adjust, and/or modify the response using the clientidentifier 306(1). For instance, the device 302 may update the responseby including and/or incorporating a client identifier 306(1) for thesession (e.g., CLIENT_SESSION_ID and/or CLIENT_PCK) in a set-cookiefield (e.g., set-cookie HTTP header). In one example, responsive toreceiving the response from the server 106, the device 302 may parse theresponse to determine and/or identify the second URL(s). For each secondURL in the response, the device 302 may obfuscate, obscure, and/orrandomize the second URL (e.g., using a hash function and/or encryption)into a string. In some embodiments, obfuscating each second URL into astring may comprise obfuscating and/or removing path and/or directorystructure information in the second URL. As such, the obfuscated/removedpath and/or directory structure information of the second URL can beinaccessible to the client 102. Responsive to determining the string(s),the device 302 may replace, exchange, change, and/or substitute eachsecond URL in the response with a corresponding string.

In some embodiments, the device 302 may obfuscate the second URL into astring by generating, configuring, and/or determining a URL identifier(e.g., UNIQUE_URL_NUMBER). The URL identifier can be unique to eachsecond URL in the response. In certain embodiments, the device 302 canuse the URL identifier(s) to generate a corresponding string for eachsecond URL. For example, the device 302 may apply a hash function on acombination of the URL identifier(s), the client identifier 306(1),and/or the domain name of the server 106. As such, for each second URL,the device 302 may apply the hash function (e.g., to obtain a string,such as a hash value) to a corresponding URL identifier, the clientidentifier 306(1), and/or the domain name of the server 106. Responsiveto generating the string(s) (e.g., for obfuscating the second URL(s)),the device 302 can maintain, store, and/or track the mapping and/orassociation between each string and a corresponding second URL. Forinstance, the device 302 can maintain the mapping in mapping data forthe session. In some embodiments, a particular string can indicateand/or identify a specific second URL (e.g., due to the unique URLidentifier). As such, each string is unique to a corresponding secondURL.

In some embodiments, the device 302 may obfuscate the second URL into astring by generating, configuring, and/or determining a first encryptionkey. The first encryption key can be determined according to (or byusing) the client identifier 306(1) and/or a key of the device 302. Forinstance, the first encryption key may include or correspond to acombination of the client identifier 306(1) and/or the key of the device302. In some embodiments, the device 302 can preconfigure, secure and/orstore the key of the device 302 (e.g., in a cache of the device 302),and as such, the client 102 may be unable to access/use the key 308(e.g., to compute a first/second encryption key). Responsive togenerating the first encryption key, the device 302 may generate thestring(s) by performing encryption using the second URL(s) and/or thefirst encryption key. For instance, the device 302 may generate anencrypted version of the second URL(s) by encrypting each second URLusing the first encryption key. Once obfuscation of the second URL(s)into the second URL(s) is performed, the device 302 may replace eachsecond URL in the response with a corresponding string (e.g., anencrypted version of the second URL).

Referring now to operation (608), and in some embodiments, the device302 may receive/obtain a second request with a candidate clientidentifier 306(2). For instance, the device 302 may receive a secondrequest (e.g., HTTP GET request) from a client 102 (e.g., the client 102sending the first request and/or other client devices 102). The secondrequest may include and/or provide a candidate client identifier 306(2)(e.g., as a cookie in a header of the second request for instance)and/or a third URL. Responsive to receiving the second request, thedevice 302 may determine whether the second request is valid byperforming a primary validation/authentication (e.g., first level check)of the second request. For example, the device 302 may determine whetherthe candidate client identifier 306(2) from the second request (e.g., ina set-cookie field) matches (or is within a defined range/extent of) theclient identifier 306(1) (610). If the candidate client identifier306(2) fails to match the client identifier 306(1), the device 302 maydetermine the second request is invalid, and therefore can prevent theserver 106 from receiving the second request (612). By preventing theserver 106 from receiving the request (e.g., the second request), thedevice 302 may prevent the client(s) 102 from accessing information fromone or more resources 304. As such, based on a comparison of the clientidentifiers 306 (e.g., client identifier 306(1) and candidate clientidentifier 306(2)), the device 302 may determine whether the client 102has authorization to access the URL included in the request (e.g., asecond request).

In some embodiments, the candidate client identifier 306(2) can matchthe client identifier 306(1). If the candidate client identifier 306(2)matches the client identifier 306(1), the device 302 may perform asecondary validation/authentication (e.g., second level check) of thesecond request. For instance, the device 302 may determine whether thesecond URL is recoverable using the third URL (614). In one example, thedevice 302 may determine whether the second URL is recoverable bydetermining whether the third URL (e.g. a hash value) is in the mappingdata as a string. The third URL in the mapping data (e.g., as a string)can be associated with at least one second URL from the response. If thethird URL is in the mapping data, the device 302 may recover, extract,and/or obtain the second URL from the mapping data according to thestring and/or the mapping. For instance, the device 302 may determine asecond URL from the mapping data that is associated/mapped to a certainstring, wherein the string includes or corresponds to the third URL. Inanother example, the device 302 may determine whether the second URL isrecoverable by generating and/or determining a second encryption keyusing the candidate client identifier 306(2) and/or the key of thedevice 302 (e.g., combining/appending the candidate client identifier306(2) and/or the key of the device). Responsive to generating thesecond encryption key, the device 302 may perform decryption of thethird URL using the second encryption key. If the second URL isunrecoverable by the above methods, the device 302 may determine thatthe second request is invalid (e.g., drop the second request) (612). Forexample, a failure of the decryption may be indicative that the secondURL is unrecoverable using the third URL.

Referring now to operation (616), and in some embodiments, if the secondURL is recoverable using the third URL, the device 302 may update,adjust, and/or modify the second request, thereby removing obfuscationin the second request. For instance, the device 302 can update thesecond request by replacing and/or exchanging the third URL in thesecond request with at least one recovered second URL. Once the device302 updates the second request, the device 302 may allow the server 106to receive the second request (618). In one example, the device 302 maysend, transmit, forward, and/or communicate the updated (un-obfuscated)second request to the server 106. By allowing the server 106 to receivethe second request, the device 302 may allow the client 102 toaccess/use/traverse one or more resources 304 of the server 106 (e.g.,the resource(s) 304 associated with the third URL(s) of the secondrequest).

Various elements, which are described herein in the context of one ormore embodiments, may be provided separately or in any suitablesubcombination. For example, the processes described herein may beimplemented in hardware, software, or a combination thereof. Further,the processes described herein are not limited to the specificembodiments described. For example, the processes described herein arenot limited to the specific processing order described herein and,rather, process blocks may be re-ordered, combined, removed, orperformed in parallel or in serial, as necessary, to achieve the resultsset forth herein.

It should be understood that the systems described above may providemultiple ones of any or each of those components and these componentsmay be provided on either a standalone machine or, in some embodiments,on multiple machines in a distributed system. The systems and methodsdescribed above may be implemented as a method, apparatus or article ofmanufacture using programming and/or engineering techniques to producesoftware, firmware, hardware, or any combination thereof. In addition,the systems and methods described above may be provided as one or morecomputer-readable programs embodied on or in one or more articles ofmanufacture. The term “article of manufacture” as used herein isintended to encompass code or logic accessible from and embedded in oneor more computer-readable devices, firmware, programmable logic, memorydevices (e.g., EEPROMs, ROMs, PROMs, RAMs, SRAMs, etc.), hardware (e.g.,integrated circuit chip, Field Programmable Gate Array (FPGA),Application Specific Integrated Circuit (ASIC), etc.), electronicdevices, a computer readable non-volatile storage unit (e.g., CD-ROM,USB Flash memory, hard disk drive, etc.). The article of manufacture maybe accessible from a file server providing access to thecomputer-readable programs via a network transmission line, wirelesstransmission media, signals propagating through space, radio waves,infrared signals, etc. The article of manufacture may be a flash memorycard or a magnetic tape. The article of manufacture includes hardwarelogic as well as software or programmable code embedded in a computerreadable medium that is executed by a processor. In general, thecomputer-readable programs may be implemented in any programminglanguage, such as LISP, PERL, C, C++, C#, PROLOG, or in any byte codelanguage such as JAVA. The software programs may be stored on or in oneor more articles of manufacture as object code.

While various embodiments of the methods and systems have beendescribed, these embodiments are illustrative and in no way limit thescope of the described methods or systems. Those having skill in therelevant art can effect changes to form and details of the describedmethods and systems without departing from the broadest scope of thedescribed methods and systems. Thus, the scope of the methods andsystems described herein should not be limited by any of theillustrative embodiments and should be defined in accordance with theaccompanying claims and their equivalents.

1. A method comprising: receiving, by a device intermediary between aclient device and a server in a session, a first request from the clientdevice that includes a first uniform resource locator (URL) of theserver; receiving, by the device, a response from the server thatincludes a second URL; updating, by the device, the response byincluding a client identifier uniquely identifying the client device forthe session in a set-cookie field, obfuscating the second URL into astring, and replacing the second URL in the response with the string;receiving, by the device, a second request that includes a candidateclient identifier, and a third URL; and determining, by the device,whether the second request is valid by: matching the candidate clientidentifier with the client identifier and determining whether the secondURL is recoverable using the third URL.
 2. The method of claim 1,comprising: determining, by the device, a match between the candidateclient identifier and the client identifier; and determining, by thedevice responsive to the match, whether the second URL is recoverableusing the third URL.
 3. The method of claim 2, comprising, when thesecond URL is recoverable: updating, by the device, the second requestby replacing the third URL in the second request with the second URLrecovered using the third URL; and sending, by the device, the updatedsecond request to the server.
 4. The method of claim 1, whereinobfuscating the second URL into a string comprises: generating, by thedevice, a URL identifier unique to the second URL; and generating, bythe device, the string by applying a hash function on a combination ofthe URL identifier, the client identifier and a domain name of theserver.
 5. The method of claim 4, comprising: maintaining, by the devicein mapping data for the session, a mapping between the string and thesecond URL.
 6. The method of claim 5, wherein determining whether thesecond URL is recoverable using the third URL comprises: determining, bythe device, whether the third URL is in the mapping data as the string;and recovering, by the device, the second URL from the mapping dataaccording to the string and the mapping.
 7. The method of claim 1,wherein obfuscating the second URL into a string comprises: generating,by the device, a first encryption key using the client identifier and akey of the device; and generating, by the device, the string byperforming encryption using the second URL and the first encryption key.8. The method of claim 7, wherein determining whether the second URL isrecoverable using the third URL comprises: generating, by the device, asecond encryption key using the candidate client identifier, and the keyof the device; and performing, by the device, decryption of the thirdURL using the second encryption key.
 9. The method of claim 8, wherein afailure of the decryption is indicative that the second URL isunrecoverable using the third URL.
 10. The method of claim 1, whereinobfuscating the second URL into a string comprises obfuscating orremoving path or directory structure information in the second URL, frombeing accessible at the client device.
 11. A device intermediary betweena client device and a server, comprising: at least one processorconfigured to: receive, in a session, a first request from the clientdevice that includes a first uniform resource locator (URL) of theserver; receive a response from the server that includes a second URL;update the response by including a client identifier uniquelyidentifying the client device for the session in a set-cookie field,obfuscating the second URL into a string, and replacing the second URLin the response with the string; receive a second request that includesa candidate client identifier, and a third URL; and determine whetherthe second request is valid by matching the candidate client identifierwith the client identifier and determining whether the second URL isrecoverable using the third URL.
 12. The device of claim 11, wherein theat least one processor is configured to: determine a match between thecandidate client identifier and the client identifier; and determine,responsive to the match, whether the second URL is recoverable using thethird URL.
 13. The device of claim 12, wherein when the second URL isrecoverable, the at least one processor is configured to: update thesecond request by replacing the third URL in the second request with thesecond URL recovered using the third URL; and send the updated secondrequest to the server.
 14. The device of claim 11, wherein the at leastone processor is configured to obfuscate the second URL into a string,by: generating a URL identifier unique to the second URL; and generatingthe string by applying a hash function on a combination of the URLidentifier, the client identifier and a domain name of the server. 15.The device of claim 14, wherein the at least one processor is configuredto: maintain, in mapping data for the session, a mapping between thestring and the second URL.
 16. The device of claim 15, wherein the atleast one processor is configured to determine whether the second URL isrecoverable using the third URL, by: determining whether the third URLis in the mapping data as the string; and recovering the second URL fromthe mapping data according to the string and the mapping.
 17. The deviceof claim 11, wherein the at least one processor is configured toobfuscate the second URL into the string, by: generating a firstencryption key using the client identifier and a key of the device; andgenerating the string by performing encryption using the second URL andthe first encryption key.
 18. The device of claim 17, wherein the atleast one processor is configured to determine whether the second URL isrecoverable using the third URL, by: generating a second encryption keyusing the candidate client identifier, and the key of the device; andperforming decryption of the third URL using the second encryption key.19. A non-transitory computer readable medium storing programinstructions for causing at least one processor of a device intermediarybetween a client device and a server to: receive, in a session, a firstrequest from the client device that includes a first uniform resourcelocator (URL) of the server; receive a response from the server thatincludes a second URL; update the response by including a clientidentifier uniquely identifying the client device for the session in aset-cookie field, obfuscating the second URL into a string, andreplacing the second URL in the response with the string; receive asecond request that includes a candidate client identifier, and a thirdURL; and determine whether the second request is valid matching thecandidate client identifier with the client identifier and determiningwhether the second URL is recoverable using the third URL.
 20. Thenon-transitory computer readable medium of claim 19, wherein the programinstructions cause the at least one processor to: determine a matchbetween the candidate client identifier and the client identifier; anddetermine, responsive to the match, whether the second URL isrecoverable using the third URL.